Single-unit solar water heating device

ABSTRACT

A solar water heater including an angularly inclined housing structure. The housing structure includes an inlet for receiving water and an outlet for discharging heated water. Encased within the housing, lies a plurality of heating pipes for absorbing solar energy. The plurality of heating pipes is operatively connected to the fluid inlet. The plurality of heating pipes encompasses a plurality of water storing pipes disposed therein. The plurality of water storing pipes is in fluid communication with the plurality of heating pipes and the fluid outlet. In this manner, the plurality of heating pipes act as a solar receiver, and the enclosed plurality of water storing pipes act as a storage tank. A solar water heating and storage device wherein a solar receiver and water storage tank are integrated into a single unit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a solar water heater. More particularly, it pertains to a unitary solar heating and storing device. More specifically, water or any other liquid or gas could be heated.

2. Description of Prior Art

Numerous variations have been developed for solar water heaters. Typically, such devices include a housing comprising two primary, yet independent, components, interconnected to each other via a duality of passageways. More specifically, solar water heaters include a vertically oriented solar receiver for absorbing heat and conducting water, and a thermally insulated storage tank usually disposed immediately above the solar receiver. Solar receivers commonly include a series of equidistantly disposed, parallel heating pipes, thermo-mechanically connected to a blackened radiator.

Such solar water heaters generally operate in a similar manner. The radiator absorbs solar energy, and heat is then imparted to the water within the pipes by conduction. In turn, the heated water decreases in density and begins to rise towards an upper passageway and into the storage tank. As the process continues, the cooler water within the tank is gradually displaced by the hotter and less dense, incoming water. As a result, the displaced cooler water descends towards a bottom passageway and into the heating pipes to be reheated. In this manner, hot and cold water continue to circulate so long as there is an appropriate temperature variance between the water within the solar receiver and that within the storage tank.

Numerous embodiments of the aforementioned solar heater exist. For instance, solar water heaters may additionally utilize heat exchangers for heating the water, or such heaters may simply differ in construction. Notwithstanding the fact that many improvements have significantly increased the overall efficiency of solar water heaters, various drawbacks remain. For example, in the known embodiments, the heated water must flow through passageways, panels, heat exchangers, or the like, prior to entering the hot water storage tank. One drawback of such embodiments is that various impediments, e.g., friction, turbulence, drag, etc., hinder the water flow. Moreover, significant energy losses occur due to the connection of radiators, and/or the utilization of external water tanks and heat exchangers. Such energy losses result during the absorption of solar energy and its transformation to heat.

Therefore, in order to promote the efficient use of energy, minimize cost, and reduce overall space, it would be advantageous to provide a unitary solar water heater, wherein external water tanks and radiators are not required.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a solar water heater including an angularly inclined housing structure. The housing structure includes an inlet for receiving water (or any other liquid or gas) and an outlet for discharging heated water. Encased within the housing, lies a plurality of heating pipes for absorbing solar energy. The plurality of heating pipes is operatively connected to the fluid inlet. Additionally, the plurality of heating pipes encompasses a plurality of water storing pipes disposed therein. The plurality of water storing pipes is in fluid communication with the plurality of heating pipes and the fluid outlet.

In this manner, the plurality of heating pipes act as a solar receiver, and the enclosed plurality of water storing pipes act as a storage tank. Hence, a solar water heating and storage device is provided wherein a solar receiver and water storage tank are integrated into a single unit.

Other objects, features, and advantages of the present invention will become readily apparent from the following detailed description in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the preferred embodiment;

FIG. 2A is a cross-sectional view illustrating the internal construction of the plurality of heating pipes;

FIG. 2B is an enlarged cross-sectional view of the internal construction of the plurality of heating pipes shown in FIG. 2A taken along lines 3-3;

FIG. 3 is a cross-sectional view of another embodiment, wherein the peak and valley portions are squared; and

FIG. 4 is a cross-sectional view of another embodiment, wherein pipe-like channels formed from steel enclose pipes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring generally to FIGS. 1-2, where like numerals indicate like and corresponding elements, a solar water heating and storage device in accordance with the invention is illustrated as including a unitary housing structure 10. Any other liquid or gas could be heated in accordance with the present invention. The housing structure 10 includes a plurality of elongated heating pipes 12 disposed therein. Preferably, the plurality of elongated heating pipes 12 are equidistantly spaced apart and in parallel with each other. The heating pipes 12 can be formed from various materials known in the art, such as galvanized iron, stainless steel, copper, or other suitable material. Additionally, each heating pipe 12 comprises an external, heat-attracting surface 40 for absorbing solar energy. The heat-attracting surface can be formed with a suitable black paint or other selective absorbing material. The housing structure 10 can be in the form of a greenhouse box.

The housing structure 10 further includes a transparent cover 20, which may be composed of glass, plastic, or the like. If desired, the transparent cover 20 can include an anti-reflective coating. One embodiment of the present invention contemplates a transparent cover 20 comprising a pair of glass panes slightly spaced apart to define an intermediate gap. The gap can comprise thermal insulating means such as, but not limited to, air, gas, or vacuum. Importantly, and notwithstanding the embodiment, the housing structure 10 is angularly positioned such that the transparent cover 20 is exposable to the sun. In this manner, as sunlight passes through the transparent cover 20, the heat-attracting surface 40 of the plurality of elongated heating pipes 12 absorbs solar radiation.

In order to minimize energy losses and maximize heat efficiency, the housing structure 10 includes thermal insulation 42. In one aspect of this invention, thermal insulation is provided to cover the areas of the heating pipes not exposable to sun. In this manner, thermal insulation can be efficiently provided to simply surround the areas wherein heated water is stored.

As best illustrated in FIGS. 2A and 2B, the plurality of elongated heating pipes 12 encases a plurality of elongated water storing pipes 14 of smaller diameter. In one embodiment, the plurality of elongated water storing pipes 14 are fixedly disposed on an internal, bottom surface of the plurality of elongated heating pipes 12, such that the water storing pipes 14 are eccentrically positioned within. Each water storing pipe 14 includes a first open end 24, and a second, opposite open end 34. The plurality of elongated water storing pipes 14 can be formed from polyvinyl chloride (PVC), polybutylene (PB), or other suitable compressible material.

The plurality of elongated heating pipes 12 and the plurality of elongated water storing pipes 14 fluidly communicate with each other via a pair of collectors 16, 18. Both collectors 16, 18 are defined by fluid passageways adapted to receive and transfer fluid. In the preferred embodiment, each heating pipe 12 is interconnected to a bottom collector 16 at one end 22, and to an upper collector 18 at a second opposite end 32. The bottom collector 16 is operatively connected to a fluid inlet 26, wherein cool water enters the solar water heating and storage device via the bottom collector 16. The upper collector 18 is operatively connected to a fluid outlet 28 for dispensing hot water. For instance, if the invention is adapted to a water faucet, hot water exits the fluid outlet 28 and enters a hot water circuit connected to the faucet. Preferably, the housing structure 10 is angled so as to facilitate fluid flow via the process of natural convection.

Analogous to the plurality of elongated heating pipes 12, various materials can be used to construct the bottom and upper collectors 16, 18, including, but not limited to, galvanized iron, stainless steel, copper, or other suitable material. If desired, the collectors 16, 18 can also include an external, heat-attracting surface 40. Further, the heating pipes 12 and collectors 16, 18 may be interconnected by various means known in the art. For example, the two may be glued, welded, clamped, screwed, etc. Similar means may also be employed for securing the collectors 16, 18 and the plurality of elongated heating pipes 12 within the housing structure 10.

In operation, the heat-attracting surfaces 40 of the plurality of elongated heating pipes 12 absorb solar radiation. Via conduction, this absorbed energy is transferred to a volume water located in-between the heating pipes 12 and the water storing pipes 14. As the aforementioned water becomes hotter, it expands and becomes less dense. By the process of natural convection, the heated water then rises and flows into the upper collector 18. In turn, the heated water advances through the upper collector 18 and subsequently enters, via the second open end 34 of the water storing pipes 14, into a cooler volume of water stored within the water storing pipes 14.

Simultaneously, due to its greater density, the cooler volume of water within the water storing pipes 14 begins to descend. The cool water exits the water storing pipe 14 via the first open end 24, and advances into the bottom collector 16. In turn, the cooler water flows throughout the bottom collector 16 and enters the volume of water located in-between the heating pipes 12 and the water storing pipes 14, wherein the cooler water is heated in the foregoing manner. Generally, so long as sunlight is present, solar radiation will generate a temperature differential between the two bodies of water, i.e., the volume of water in-between the heating pipes and water storing pipes, and that within the water storing pipes. As such, water will continue to circulate in accordance with the aforementioned process.

By encasing the plurality of elongated water storing pipes 14 within the plurality of elongated heating pipes 12, the former set of pipes 14 functions as a water storing tank, and the latter functions as a solar receiver. Accordingly, integrating the two sets of pipes eliminates the need for providing a separate component for storing water. Such integration not only decreases overall surface area and thereby the costs generated by additional components, but moreover, significantly reduces energy losses and other common drawbacks associated with solar water heaters known in the art.

The present invention additionally contemplates a nearly identical solar heating and water storing device, as shown in FIGS. 3 and 4. In this embodiment, however, the solar receiver component has been modified by the elimination of the plurality of elongated heating pipes 12, and substituted with a metal sheet composite 38. The metal sheets 38 can be bent, pressed, stamped, or otherwise fabricated to provide a rippled configuration. The rippled configuration includes peaks having a top surface 44 and a bottom surface 46. When viewed in cross-section, the top and bottom surfaces 44, 46 include alternating peak and valley portions. As illustrated in FIGS. 3 and 4, depending on the fabrication method, these peak and valley portions can be squared, curved, or otherwise shaped. A flat metal sheet 36 having an external heat-attracting surface is optionally mounted over each of the top and bottom surfaces 44, 46 as shown in FIG. 3. Accordingly, the combination of the flat metal sheet 36 with the foregoing surfaces 44, 46 defines a series of corrugated grooves 50 wherein the plurality of water storing pipes 14 are encased therein alternating along the bottom surface 46 and the metal sheet 38 in mounted connection with the bottom surface 46. Alternatively, as shown in FIG. 4, two metal sheets 38 can be combined with the top surface 44 of one metal sheet 38 in contact with the bottom surface 46 of a second metal sheet 38, thereby forming the corrugated grooves 50. In operation, the corrugated grooves 50 act as fluid passageways wherein incoming water is heated in the same manner as outlined above.

The aforementioned metal sheets can be welded, glued, brazed, soldered, or otherwise joined together and mounted within the housing. One advantage provided by this embodiment is the reduction of the high costs associated with manufacturing a plurality of metallic pipes. This is especially true when the plurality of elongated water storing pipes is formed out of plastic-like material, since the composition of metal sheets entirely eliminates the need for utilizing metallic heating pipes. Hence, the foregoing embodiment provides a simpler and more cost efficient means for producing a solar water heating and storage device in accordance with the present invention.

In another embodiment of the present invention, the bottom collector 16 comprises an electrical heating element for maintaining heat during prolonged lapses of sunshine. If desired, the electrical heating element can include standard safety interlocks disposed in either the bottom collector 16 or the upper collector 18. For example, the electrical heating element can include a thermostat for regulating water temperature. Additionally, the electrical heating element can include a pressure regulator for maintaining water pressure within a maximum allowable level.

In order to provide instant hot water, the electrical heating element can be installed within the upper collector 18. With regard to this embodiment, the electrical heating element is preferably equipped with a flow switch sensitive to water flow. The flow switch can be installed in either the fluid inlet 26 or the fluid outlet 28. Analogous to the thermostat and pressure regulator, the flow switch also functions as a safety interlock. For example, when hot water is drawn out, the flowing hot water actuates the switch so that the electrical heating element receives electrical power and heats the water exiting the upper collector 18. Furthermore, when the hot water circuit is closed, the flow switch automatically turns off the electrical power.

The invention has been described in an illustrative manner, and it is to be understood the terminology used is intended to be in the nature of description rather than of limitation.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. For instance, while the present invention is more particularly directed to a solar water and heating device, the foregoing disclosure is also applicable to a heat exchanger. It is, therefore, to be understood that within the scope of the appended claims, the invention can be practiced otherwise than as specifically described. 

1. A solar water heating and storage device comprising: a housing including a fluid outlet for discharging heated water; a plurality of heating pipes encased within said housing, said plurality of heating pipes operatively connected to a fluid inlet; and a plurality of water storing pipes encased within said plurality of heating pipes and in fluid communication with said plurality of heating pipes and said fluid outlet.
 2. A solar water heating and storage device according to claim 1, further comprising a bottom collector and an upper collector, said bottom collector interconnected to and in fluid communication with a first end of each said heating pipes, and said upper collector interconnected to and in fluid communication with a second opposite end of each said heating pipes.
 3. A solar water heating and storage device according to claim 2, wherein said plurality of water storing pipes are eccentrically encased within said plurality of heating pipes.
 4. A solar water heating and storage device according to claim 3, wherein said upper collector includes a liquid flow passage adapted to transfer heated water from said plurality of heating pipes to said plurality of water storing pipes, and said bottom collector includes a liquid flow passage adapted to transfer cool water from said plurality of water storing pipes to said plurality of heating pipes.
 5. A solar water heating and storage device according to claim 4, wherein said plurality of heating pipes, said upper collector, and said bottom collector individually include an external heat-absorbing surface.
 6. A solar water heating and storage device according to claim 5, wherein said housing further includes a transparent cover exposable to sunlight, said transparent cover disposed over said plurality of heating pipes, whereby said external heat-absorbing surfaces of said plurality of heating pipes absorb solar radiation entering via said transparent cover, thereby heating a volume of water in direct contact with said plurality of heating pipes.
 7. A solar water heating and storage device according to claim 6, wherein said housing further includes thermal insulating means for covering an area of the externally blackened surfaces not exposable to sunlight, said thermally insulating means disposed within said housing.
 8. A solar water heating and storage device according to claim 7, wherein said plurality of heating pipes are arranged in a substantially parallel configuration.
 9. A solar water heating and storage device according to claim 8, wherein said plurality of water storing pipes are fabricated out of a plastic.
 10. A solar water heating and storage device according to claim 9, wherein said transparent cover includes a pair of glass panes having a gap therethrough, said gap filled with means for providing thermal insulation therein.
 11. A solar water heating and storage device according to claim 10, wherein said pair of glass panes further includes an anti-reflective coating.
 12. A solar water heating and storage device according to claim 11, wherein said bottom collector encases an electrical heating element having a standard safety interlock.
 13. A solar water heating and storage device according to claim 1, further including a sheet member having a rippled configuration defining peaks having top and bottom surfaces, said top and bottom surfaces including peak and valley portions when viewed in cross-section, said device further including a flat sheet mounted over each of said top and bottom surfaces, whereby the combination of said valley portions in each of said sides of said sheet member with said flat sheets define said heating pipes.
 14. A solar water heating and storage device according to claim 13, wherein said peak and valley portions are squared in cross-section.
 15. A solar water heating and storage device according to claim 13, wherein said peak and valley portions are rounded in cross-section.
 16. A method of making a solar water heating and storage device comprising the steps of: providing a sheet member having a top and a bottom surface; forming said sheet member to provide a rippled configuration, said rippled configuration defining a plurality of longitudinal corrugated grooves. encasing a plurality of water storing pipes having a first open end and a second open end within said plurality of longitudinal corrugated grooves; mounting a flat sheet over said top and bottom surfaces of said sheet member; covering said flat sheets with heat-absorbing material; disposing said sheet member within a housing having a transparent cover; and interconnecting said sheet member to a bottom collector at one end, and to an upper collector at a second opposite end, wherein said bottom collector is operatively connected to a fluid inlet for receiving water, and said upper collector is operatively connected to a fluid outlet for dispensing hot water.
 17. A method of making a solar water heating and storage device according to claim 16, wherein said longitudinal corrugated grooves include square corners.
 18. A method of making a solar water heating and storage device according to claim 16, wherein said longitudinal corrugated grooves included rounded corners.
 19. A heat exchanger comprising: a plurality of heating pipes operatively connected to a fluid inlet, and a plurality of water storing pipes eccentrically encased within said plurality of heating pipes and in fluid communication with said plurality of heating pipes.
 20. A solar water heating and storing device comprising: a housing made as a greenhouse box containing a heat exchanger according to claim 19, including a cold water inlet and hot water dispensing outlet. 